氧化亚铁硫杆菌(SH-T)氧化毒砂的机理

Mechanism on biooxidation of arsenopyrite with Thiobacillus ferrooxidans strain SH-T

采用优良的氧化亚铁硫杆菌SH T菌株对含金毒砂抛光片和纯毒砂粉末进行氧化试验 ,并作了定时定域的显微观察分析 ,研究了每一阶段毒砂表面的性质和毒砂氧化膜的形成过程。毒砂在细菌氧化后覆盖了黄色氧化膜 ,抑制了细菌的快速氧化。用X射线粉晶衍射法对细菌氧化产物进行物相分析 ,结果表明氧化物的主要成分为黄钾铁矾 ,其次为砷华。细菌氧化膜的X射线光电子谱分析表明毒砂晶体中As表现出 [AsS]2 -→As(Ⅲ )→As(Ⅴ )的价态变化过程 ,揭示了细菌氧化过程中毒砂形貌变化规律和晶体的内在联系。

Bacterial oxidation tests of the polished sections of gold bearing arsenopyrite and pure arsenopyrite powder were conducted with a fine thiobacillus ferrooxidans named SH T. The arsenopyrite polished sections during the whole process of bacterial oxidation were observed and analyzed at 12 h intervals under the microscope in order to study the surface character of arsenopyrite at the every phase and the formation course of oxidation film on the crystal surface. The compositions of oxidation film which could restrain biooxidation of arsenopyrite were indicated as jarosite and arsenolite by XRD. After the arsenopyrite crystals are oxidized, As state of the arsenopyrite crystal are transformed from [AsS] 2- and As(Ⅲ) to As(Ⅴ), which reveals the oxidation regularity of the arsenopyrite surface and its inner relation. [